Problem with new Amana 18 SEER heat pump

[dj1993]

We just had a new Amana 18 SEER heat pump installed in our Southern Indiana home Jan 3 and have had nothing but problems ever since. Condensing unit is ASZC180481AC, Air Handler is AVPTC426014AA and ComfortNet communicating thermostat #CTK01AA. We replaced an older 12 SEER 3 ton Bryant heat pump that was having issues. We have a 1647 SF one-story home (over a crawl space)that we bought 3 years ago and gutted 90% of it and reinsulated prob. 90% of all exterior walls, installed new construction Low E argon-filled windows and replaced all but one exterior door. Needless to say, the house is not drafty. We had a larger 4 ton unit installed because we are adding an addition onto the house this spring. We also had all new duct work installed because we previously did not have any cold air returns in the house.

Now the issue. Our first electric bill was $438 from 12/15 to 1/19 (avg 117.85 kw/day and Avg daily temp 39). We had to run on EM heat strips (10 Kw) from 12/15 to 1/3 when the new heat pump was installed. The new heat pump constantly cycled on & off. Sometimes it was 3 minute on/off cycles and sometimes at night it would be off for 10 min & then run for hours. We had it set at 68-70. We had the installers out at least 2-3 times each week during January because of the constant cycling. It warmed the house, but it ran at least half the time.

Between 1/19 (when the meter was read) and 1/29, we used 1186 Kw (Avg 118.6 Kw/day). We talked to the installers again and said something had to be done because we were using as much electricity as we had when we were running on EM heat strips with the old unit! They were calling Amana and trying various suggestions. Nothing helped. We finally said we wanted another unit and they agreed to replace it.

New unit installed 2/8 and nothing has changed. It was still running short cycles. Amanda tech rep here on 2/10 (left vehicle running in the driveway and brought nothing but a notepad). Suggested running shielded new thermostat wire because he thought it was high voltage interference. Told us that there was no way this unit was causing our high electric usage and left. Wire changed -- no change. Between 2/8 & 2/14 we used 712 Kw (Avg 118 Kw/day). In desperation, we turned off the furnace on 2/14 for 24 hours and continued to use everything else as normal. Used 50 Kw in 24 hours and temp in house dropped 11 degrees.

Does anyone have any idea what could be causing the constant cycling and high electric usage? Thermostat does not show EM being used at any time.

[Special Ed]

Are you getting any error messages on your tstat? The system has a wonderful system of diagnostic lights that usually are quite capable of pointing techs in the general direction of what's wrong....

[dj1993]

Not according to the installer or the Amana tech rep. We have used 3 different ComfortNet thermostats and they tried another (I think) Honeywell that was a non-communicating tstat. We had the same issues no matter what tstat was used.

They tried recharging the first unit. They have now put in 2 drops in our crawl space just to see if it made any difference because the installer was getting told it was because the system was too large for our current space. No change in constantly cycling. The warmer it is, the less it cycles. When the temp outside gets below 35-40 degrees, that is when it really begins to cycle on and off. Frequently, the cycles are around 14 min. on & 14 min. off.

[dj1993]

The installer has run out of ideas. The factory rep doesn't seem to have any idea. Last night, the unit ran for 4 hours continuously and the outside temp was 38 when it started and 34 when I finally turned the thermostat down from 68 to 66 so it would stop running for a while and went to bed.

[skippedover]

On what basis was the unit up sized to 4.0-tons. I know you said you're going to add on but did they do a real room-by-room load analysis or just assume since you said you're adding on, that you needed a 4.0-ton system? If they did do a load analysis, did the design the new ducts to Manual 'D'? Does your thermostat give you the static pressure in the system? If so, what is it? If not, you should request a static pressure check because a variable speed blower motor pushing against a high static will eat HUGE amounts of electricity. Variable speed blowers are great but they cannot tolerate undersized ducts that result in high static pressures. This is a 2-stage system so does your t-stat show it as operating in 1st stage or 2nd stage at 38°F? If it's short cycling, are your positive it's not locked into 2nd stage below 40° or some such? It would be called HP latch up temperature in all likelihood. FYI, if the unit is approaching the 1st stage heating capacity of the system at say 34°F, I'd expect it to be operating non-stop or nearly so. When it can no longer hold set-point on 1st stage, it should then cycle up to 2nd stage for a while and then again stage down to 1st stage. That would be constant operation, just maintaining room temperature but also be normal operation for a 2-stage system.

[Special Ed]

Well, I'm sorry, but I'd have to take a look @ it personally to get some kind of idea.
My first instinct is that something's not wired right or set up right....

[beenthere]

You have a house that probably needs 2.5 tons since you made those improvements. That has a 4 ton unit, that has no place to go with the air it needs to move.

A bit late now. But almost always better for any sizable addition to have its own unit.

Probably about the only thing o do besides tear it out and get a properly sized one. is to have them dump all of the excess air to the crawlspace, and add returns to it to get the air flow up to where it should be.

[dj1993]

We told them we had a 3 ton system and explained the size of the room addition (500 SF) that we were planning. We do have a vaulted ceiling in our great room/dining room area and regular 8 ft ceilings throughout the rest of the house.

They did not do any load analysis and NONE of the 8 companies that we got estimates from said anything about doing one. They all said we needed a 4 ton unit so we assumed it was what we needed.

We have asked them to do a static pressure test and they have not done one. The factory rep did not suggest one and he said there was sufficient cold air returns (Of course, again, he left his vehicle running in the driveway so he did not anticipate staying very long). He said everything was running like it should but could not explain the frequent run times. They have removed the pleated air filter and left it open to see if it was because of restricted air flow. No change. Now they have installed 2 drops into our crawlspace to compensate for the oversized unit. No change.

When it is running in these short cycles, it is primarily running in 1st stage. It will occasionally ramp up to 2nd stage for a minute or two and then goes back to 1st stage.

[beenthere]

They sized you by sq ft. not by the heat gain and loss of your house. A 50 sq ft addition didn't/won't add 1 ton to the size you need.

In first stage, its running 75 and 80% of its full capacity.

[Gross]

id check youre airflow....then your charge. tech support doesnt like to do that

[dj1993]

They recharged the first unit they put in and it didn't change anything. They said it was very difficult to determine the charge needed in the winter but they said their head pressure was right.

Unfortunately, the installers have done all they know or have the equipment to do, apparently. The factory rep only brought a note pad and did not have any equipment to analyze anything.

We have been keeping track of run times, outside temps, etc. in an attempt to provide more information to them.

[dj1993]

The installers have told us they will put whatever (Different brand or type of heat) we want in just to make us happy. We were hoping that the first Amana 18 SEER unit was defective and the second one would work okay. Now we continue with the same issues. They have contacted Amana in Houston trying to get tech help also.

Any suggestions (size, Brand, etc.)? Natural gas is not available. Propane is an option but, due to cost, not as desirable as a heat pump.

[beenthere]

Did the old 3 ton heat and cool your house ok.

[dj1993]

Not really. We kept the thermostat lower to keep the electric bills down and our great room/dining room with the vaulted ceiling was always colder than anywhere in the house. But we also did not have any cold air returns in any of the rooms. That is why we had all new duct work put in the house and cold air returns installed in the ceilings in all the rooms. We were hoping to be able to keep it a little warmer with a little lower electric bills by going with the 18 SEER system.

[beenthere]

Duct work/air flow was probably the main problem, not unit size.

[udarrell]

How much is propane a gal there?

Evansville winter design is 4-F at 99%; 9-F at 97.5%.

Depending on price per gal, I think I might have gone with a propane furnace &, standard A/C.

Here the last propane I got was, $2.049 a gallon.

This has been a mild winter here; I use a RM-TH with a SWING temp differential setting & can control on/off cycle times &, the temp drops the way I want them.

It appears the H.P. is oversized with inadequate airflow...

[dj1993]

Not sure what propane cost is. We were just told it was double the cost of natural gas and the heat pump was less expensive to heat/cool. Plus we would lose our total electric price from our electric company.

[udarrell]

Not sure what propane cost is. We were just told it was double the cost of natural gas and the heat pump was less expensive to heat/cool. Plus we would lose our total electric price from our electric company.

Here is a link to Indiana propane prices; plus a history of prices.
http://www.eia.gov/dnav/pet/pet_pri_wfr_dcus_SIN_w.htm

There may be better pages for price comparisons, here is one:
http://www.duke-energy.com/indiana/s...ting-costs.asp

Everyone can check prices in their state; it's pretty much on target as far as WI prices are set at this winter.

This winter your prices are higher than WI prices. (Look up WI)

When you look at the pricing history, the question is; will prices go up or down.

Electrical power rates are likely to continue an upward trend.

[dj1993]

So what should we do now? We are going to be building the 500 SF room addition this spring. Is there anything we can do now since the comments seem to suggest we have an oversized unit for our present house. Demand a static pressure check? Isn't this something the Amana tech rep should have insisted they do?

We would hate to downsize to a unit that just handles our current house and then have too small a unit in a few months. We have an attached insulated garage (not as well insulated as the house though). Could we add ductwork to it for now until we add the addition or is that not a good idea? Is there any other suggestions or things we should request the installers do before going to a different manufacturer or system?

[beenthere]

The garage is not allowed to be connected to the same duct system that serves any occupied area.

Was it an actual Amana tech rep, or a tech rep from the local Amana distributor.

It will still be over size after you add your addition.